US5893948AExpiredUtility

Method for forming single silicon crystals using nucleation sites

61
Assignee: XEROX CORPPriority: Apr 5, 1996Filed: Apr 5, 1996Granted: Apr 13, 1999
Est. expiryApr 5, 2016(expired)· nominal 20-yr term from priority
Inventors:Norbert H. NickelGregory B. AndersonSteven E. ReadyJames B. BoycePing Mei
Y10S117/902C30B 29/06C30B 13/00
61
PatentIndex Score
27
Cited by
27
References
20
Claims

Abstract

The invention provides a method for forming a plurality of single silicon crystals over a substrate. The method forms a plurality of nucleation sites over the substrate. An amorphous silicon layer is formed over the substrate covering the plurality of silicon nucleation sites. The amorphous silicon layer is melted by using a laser beam and then crystallized to form the plurality of single silicon crystals. Each of the plurality of single silicon crystals correspond to one of the plurality of nucleation sites.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A method for forming a plurality of single silicon crystals over a substrate, comprising: forming a plurality of single crystal silicon nucleation sites over the substrate;   forming a first amorphous silicon layer over the substrate covering the plurality of single crystal silicon nucleation sites;   melting the first amorphous silicon layer using a first laser beam; and   crystallizing the first amorphous silicon layer to form the plurality of single silicon crystals, wherein each of the plurality of single crystal silicon nucleation sites.   
     
     
       2. The method of claim 1, wherein the step of forming the plurality of single crystal silicon nucleation sites comprises: forming a second amorphous silicon layer over the substrate;   melting the second amorphous silicon layer using a second laser beam;   crystallizing the second amorphous silicon layer into a polycrystalline silicon layer; and   forming a plurality of single crystal seed columns by patterning and etching the polycrystalline silicon layer, wherein the plurality of single crystal seed columns are the plurality of single crystal silicon nucleation sites.   
     
     
       3. The method of claim 2, wherein a thickness of the second amorphous silicon layer is about 100-200 Å. 
     
     
       4. The method of claim 2, wherein the second laser is an excimer laser. 
     
     
       5. The method of claim 2, wherein a laser fluence of the second laser beam is about 180-220 mJ/cm 2 . 
     
     
       6. The method of claim 2, wherein the plurality of seed columns have an average cross-sectional width of less than about 1000 Å. 
     
     
       7. The method of claim 6, wherein the plurality of seed columns have the average cross-sectional width of about 800-1000 Å. 
     
     
       8. The method of claim 1, wherein the step of forming the plurality of silicon nucleation sites comprises: forming a nucleation layer over the substrate;   forming an insulative layer over the nucleation layer; and   patterning and etching the insulative layer to expose a plurality of portions of the nucleation layer, the plurality of portions being the plurality of single crystal silicon nucleation sites.   
     
     
       9. The method of claim 8, wherein a thickness of the insulative layer is less than a thickness of the first amorphous silicon layer. 
     
     
       10. The method of claim 9, wherein the thickness of the insulative layer is about one half the thickness of the first amorphous silicon layer. 
     
     
       11. The method of claim 8, wherein the nucleation layer is at least one of a metal layer and a silicon nitride layer. 
     
     
       12. The method of claim 1, wherein the step of forming the plurality of single crystal silicon nucleation sites comprises: forming a third amorphous silicon layer over the substrate; and   forming a plurality of nucleation seeds in the third amorphous silicon layer, wherein the plurality of nucleation seeds are the plurality of single crystal silicon nucleation sites.   
     
     
       13. The method of claim 12, wherein the third amorphous silicon layer has a thickness of about 100-200 Å. 
     
     
       14. The method of claim 12, wherein the plurality of nucleation seeds have an average width of less than about 1000 Å. 
     
     
       15. The method of claim 12, wherein the step of forming the plurality of nucleation seeds comprises: melting a plurality of portions of the third amorphous silicon layer; and   crystallizing the plurality of portions of the third amorphous silicon layer melted by the melting step to form the plurality of nucleation seeds.   
     
     
       16. The method of claim 15, wherein melting the plurality of portions of the third amorphous silicon layer comprises: irradiating the plurality of portions of the third amorphous silicon layer using a plurality of laser beam arrays, one beam of each of the plurality of laser beam arrays irradiating one of the plurality of portions of the third amorphous silicon layer.   
     
     
       17. The method of claim 16, wherein a total laser fluence irradiating each of the plurality of portions of the third amorphous silicon layer is about 180-220 mJ/cm 2 . 
     
     
       18. The method of claim 1, wherein a thickness of the first amorphous silicon layer is about 800-1000 Å. 
     
     
       19. The method of claim 1, wherein the first laser beam is an excimer laser beam. 
     
     
       20. The method of claim 1, wherein a laser fluence of the first laser beam is about 280-440 mJ/cm 2 .

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